Experimental study on effective stiffness of reinforced concrete hollow piers
Wei Wang1 Shao Changjiang1,2 Xiao Zhenghao1 Qi Qiming1 Hu Chenxu1 Xiao Laichuan1 Wang Meng1
1. School of Civil Engineering, Southwest Jiaotong University, Chengdu 610031, China;
2. National Engineering Laboratory of Geological Disaster Prevention Technology in Land Transportation, Southwest Jiaotong University,
Chengdu 610031, China
Abstract：The existing formulas of effective stiffness are summarized, and their reasonability are discussed based on the experimental data of 35 rectangular hollow and 44 rectangular solid columns. It is found that their applicability should be further improved. According to the quasi-static test results, the different characteristics in effective stiffness between the hollow and solid columns, influence factors and the three-component yield displacement are investigated. The formulas of effective stiffness were regressed for the two types of columns with axial compression ratio, shear span ratio and as the control parameters. The applicability of the regression formulas was validated by the test results of five round-end hollow specimens. The research results show that compared with the axial compression ratio and the shearing-span ratio, the ratio of rebar, strength of longitudinal steel and concrete have less influence on the effective stiffness. The effective stiffness increases with the axial compression ratio and the shearing-span ratio, while decreases with . The regression formula I is suitable to estimate the effective stiffness of square solid piers, and formula II is applicable to predict the effective stiffness of rectangular and thin-walled round-end hollow columns.
